Asstonob to automatic electric com



J. ERICKSON. I SELECTIVE SIGNALING SYSTEM.

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APPLICATION FILED JUNE 24. I9l2.

Patented Aug.

TY'aR/VEXQ J. ERICKSON. SELECTIVE SIGNALING SYSTEM.

APPLICATION FILED JUNE 24, I912.

Patented Aug. 15, 1916.

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TOR/VEYS J. 'ERICKSON.

SELECTIVE SIGNALING SYSTEM. APPLICATION FILED 11111524. 1912.

Patented Aug. 15,1916.

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m g g IIIIIIIIIIIELE= 1111111 WITNESSES dd ANT FFTTG.

JOHN ERICKSON, 01E CHICAGO, ILLINOIS, ASSIGNUJR. T0 AUTOMATIC ELECTRIC COM- PARTY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SELECTIVE SIGNALING- SYSTEM.

Specification of Eetters Patent. Pmtp -p gfl A 15 19116 Application filed June as, 1912. serial No. 705,402.

' such systems there are a large number of stations connected to the line and station selectors are employed for selectively signaling the said stations.

Among the objects of my invention are to provide a station selector in which a large number of stations may be selectively signaled by the use or" a minimum number of operating impulses, and to otherwise increase the eiliciency oi the operation of these station selectors.

A further object of my invention is to provide a system in which the desired station is selected by first operating a plurality oi said station selectors, and then releasing all except the desired selector.

.L a. special object of my invention is to provide a station selector which may be operated by impulses of one polarity and released by impulses of the opposite or reverse polarity.

A further object is to'provide a station selector which, in certain positions, may be re leased with but a single impulse, while in other positions it is necessary to transmit a plurality of impulses to release the selector.

These and further objects of my invention will be more clearly understood by reference to the accompanying drawings and description, in which T have illustrated and described one embodiment of my invention.

Figure 1 represents diagrammatically a telephone line to which there is connected a. central ofiice operators equipment and three local stations A, A and A. Fig. 2 is a plan view of a selector switch with which each local station shown in Fig. l is provided. Fig. 3 is a side elevation of the same. Figs. 4, 5 and 6 are diagrams representing the relation of certain parts of the apparatus at various stages in its operation. Figs. and 8 are detail views ndicating the operation of the apparatus. Figs. 9 and 10 are diagrammatic representations of the controlling circuits, as will be described hereinafter.

The mechanism of the selector is mounted upon a sultable base plate 2. At one end of this plate there is mounted a polarized electromagnet comprising a permanent magnet t: and two coils 4 and 5. This electromagnet is provided with an armature 6 which is piyoted between the base plate and the bridge-piece Z. The electromagnet is held in place by clamping the end extensions of the yoke' 8 between the thumb nuts 9 and 10 and 11 and 12 on the screws 13 and 14 which are threaded into the lugs 15-and 16. With this form of mounting, the magnet is easily adgustable toward or away from its armature. Near the upper end of the plate 2 there'is a spindle 1'? which is pivoted between the plate and the bridge-piece 18, and to which spindle there is secured a ratchet wheel 19. Upon the ratchet wheel there is an insulating bushing 3? which, when the wheel is rotated to a certain position, forces the contact spring 39 into contact with the spring 38. The portion of the spindle above the ratchet wheel is threaded to receive the thumb nut 20. Clamped between the thumb nut 20 and the wheel there are two arms 21 and 22, and a third arm 23 is firmly secured to the wheel by means oil a screw 24. The outer ends of each of these arms is bent back atrightangles toward the base plate,- so as to extend into the plane of the upturned end of the arm 34 on the armatureG. Attached to the armature 6 there is a second arm 26', which carries at its end a long driving pawl 27 for rotating the ratchet wheel 19. A holding pawl 29 is provided for holding the ratchet wheel in its rotated position against the tension of the spring 28. This pawl may be released from the wheel by means of a throw off device comprising a small ratchet wheel 30 which is loosely mounted on the screw 31 and in which there is a pin 32 which extends up behind the tail-piece of the pawl 29. The ratchet wheel 30 is controlled by the pawl 33 on the arm 34 and is provided with a holding pawl 35. When the armature 6 is tipped downward to the left, the arm 26 strikes the rear ortion of the holding pawl 35 and releases 1t from the wheel 30 The wheel 30 must be rotated through a distan e the normal positions oi the arms 21, 22, 23"

equal to twicethe pitch of the teeth thereon in order to release the pawl 29 from the wheel 19. The wheel 30 may be rotated this distance by a'single stroke of thearmature if none of the arms 21, 22 or 23 are in the path of the arm 84. If, however, one of the arms 21,22 or 23 is in the path of the arm 34,

the armature 6 is prevented from completing a full stroke and can inove only far enough to rotate the wheel 30 one step.

In the diagrammatic showing m Fig. 4

and 34 are represented. Fig. 5 shows the ositions of these armsafter the wheel 19 has been rotated from its normal position to some extent, and the armature 6 drawn down to the right to its full extent, showing how the end 0 the arm 34 passes inside the path of the arms 21, 22 and 23. Fig. 6 represents the position of the arms when the wheel 19 has been rotated so as to bring the end of the arm 21 into the path of the arm 34 and the armature 6 has been drawn-down to the ri ht, showing how the armature 1s prevente from making a full stroke in this direction. The armature 6 is normally maintained in its mid-position by a spring 43 the ends of which rest upon the vertical portions of the bridge-piece 7. To the ends of the s ring 43 there are attached a couple of weights 44 and 45 which, by their inertia,

check the vibrations of the armature 6 when the magnet deiinergizes and prevents it from returnin past its normal. position to any apprecia le extent. In the normal osition of the armature 6, the pawls 27 an 33 are outside the path of the teeth on their respective wheels 19 and 30. In order to rotate the ratchet wheel 19 to cause the bushing 37 to close the contact between the springs 38 and 39 a number of impulses mustbe sent h groper di-' impulse of current is sent throu h the magnet in the opposite direction, t e armature 6 will be drawn down to the right, and unless one of the arms 21, 22 or 23 is in the path of the arm 34, the wheel 30 will be rotated 3 far enough to release the pawl 29 from the wheel 19 and allow it to return to normal position. If, however, one of the arms 21, 22 or 23 is in the path of the arm 34, the wheel 30 will be rotated only one ste which is not sufiicient to release'the whee 19. A

second impulse through the magnet in the same direction, however, would advance the wheel 30 a second ste and cause the pawl 29 to be withdrawn. f, instead of a second releasing impulse, another series of operating impulses. are sent through the magnet the wheel 19 will be again progressed an the wheel 30 allowed to return to normal position. It will thus be seen that the wheel 19 may be continuously advanced by a series of grou s of o crating impulses, each group being ollowe by a single reverse or releasing impulse, provided the releasing impulse comes in at a time when one of the arms 21, 22 or 23 is in the path of the arm 34. A releasing impulse at any other time will release the wheel 19. When one of these arms is in the path of the arm 34, the wheel 19 may be released by two consecutive release impulses. If desired, the three separate arms 21, 22 and 23 may be dispensed with and in their stead a single flat fanshaped member (Figs. 7 and 8) having three downwardly-turned projections 71, 72 and 73 may be used. This member 70 may be secured to the wheel 19, so that the projections 71, 72 and 73 will perform the functions of the inwardly-turned ends of the arms 21, 22 and 23.

A system of the kind herein shown con-. sists of a main or sending station and a lurality of local or way stations connected in bridge of the line. As shown herein, the main or despatchin station has a local battery telephone an a calling mechanism. Any suitable form of mechanical calling device may be employed, but I have represent ed the calling device herein simply by a manually-operated key. The central ofiice telephone comprises the usual receiver 46, transmitter 47, induction coil 48, battery 49 and condenser 50. The main office is also provided with a battery B for operating the selectors at the local stations. In vFig. 1

there are shown three local stations A, A

and A connected to. the line conductors 51 and 52. Each of these stations comprises a selecting switch, such as herein described,

and a telephone instrument. In Fig. 1 the selectors are represented only diagrammaticallljy.

ach station is provided with an ordinary vibrating bell 53 one terminal of which is connected with the spring 39 of the selector. The other terminal of the bell is connected to one terminal of a local battery 55, the other terminal of which is connected through the hook switch springs 56 and 67 to the selector spring 38. In order to signal any station its selector must be operated to close the contact between the springs 38 and 39 to close the circuit of the bell 53. The selectors are all preferably arranged so that the springs 38 and 39. may be closed by the same number of steps of the wheel 19, and also so that this closure shall occur when the arm 23 1s 1n the path of $1. 9 arm 34. The

mean

two artns 21 and 22 are adjusted to a slider ent po ition in each of the selectors. Accordmgly, it is to be understoodthat, all; station selectors are adapted to close their respective signaling circuits at the same time, in response to a series of im ulses inthe same direction, transmitted rom the sending station.

In order to give a clearer understanding of my invention I will explain in detail how the station A may be signaled without signaling any other station on'the line. Each station is indicated by a code number which represents themanner in which the operating impulses must be grouped to call that station. This grouping is determined by the positions of the arms 21 and 22. lit will be assumed that the code number of station .tion as at the station A A .is 345. In order to call this number the operator at the main or sending station operates the key K to close the contacts 5857 and 5960 three times momentarily, whereby three operating impulses are transmitted through the magnets of the selectors, stepping all the wheels 19 around three steps and bringing the arm 21 at the station A into the path of the arm 34. The key K is then operated to close the contacts 57--60 and 59-61, whereby one impulse is trans. mitted through all the selectors. The selector at the station A, and at all other stations where the arm 21 is in the same posiis unafl'ected by this impulse, while all other selectors will be released. The key K is now operated to transmit four more operating imlpulses, followed by a single release impu se. These 1 four operating impulses advance the arm 22 into the path of the arm 34, so that the setion A at the station A lector at the station A is not afi'ected by this release impulse. This second release impulse, however, releases all the selectors which were not released bythe first release impulse, because both of the arms 21 and 22 are not in the same position in any other selector as they are in. the selector at the sta- The key K is now operated to transmit five or more operating impulses. over the line, whereby the springs 38 and 39 are closed and the arm 23 is brought into the path of the arm 34. The closing of the springs 38 and 39 closes the circuit of the. bell 53 to signal the operator at its station. The last group of operating impulses is preferably followed by a single releasing impulse in the same manner as the previous groups of impulses. This release impulse has no efiect on the selector at the station' Aflexcept to rotate the throw-ofi' wheel 30 one step, whereby the selector may be released by a single additional release impulse after the operator has answered, or after the bell has beenrung as long as desired. When the operator at the station A responds by removing hls resol er, he breaks Witt the circuit of the whereupon conversation may be carried on between the main operator and the local operator in the usual manner.

As has been reviously stated, it is with- 1n the sec e o my invention to provide a mechanica calling device at the main or despatching' station instead of the key K, through the medium. of which calling device the operation of the selector ma be controlled. In Figs. 9 and 10 I have illustrated two different ways in which a calling device of the tgype which is employed in the so-- called trowger automatic telephone exchange, and as illustrated and described in British Patent No. 30,458 of 1909, issued to T. Gr. Martin, maybe applied to the system disclosed herein. This type of calling device, as is well known, comprises a finger hole dial and an impulse wheel, through the medium of which latter a couple of impulse springs are controlled. These impulse sprlngs are usually referred to as the vertical and rotary impulse springs, respectively, and the mechanism is so arranged that upon the operation of the device to call any digit, the vertical impulse spring is forced into contact with a stationary or ground spring a definite number of times, corresponding to the digit called, after which the rotary impulse spring is forced into contact with the ground spring once. The mechanism of this type of calling device is in general well known. In Figs. 9 and 10 T have shown simply the impulse springs. In Fig. 9 the spring 100 corresponds to the usual ground spring. The spring 101 corresponds to the usual vertical spring and the spring 102 corresponds to bell 53, bridges the receiver a circuit across. the line conductors 51 and '52 and closes the local transmitter circuit,

the usual rotary impulse spring. The spring 100 is connected toone side of the line circuit, while the other side of the line is connected to the mid point of the battery. B the two terminals of which are connected to the springs 101 and 102, respectively. It will thus be seen that upon each operation of the calling device a number-of impulses corresponding to the digit called will be transmitted from the plus terminal of the battery B through the springs 101 and 100, thence over the line and throughthe selectors 103, 104: and 105 and back to the mid point, after which a single impulse will be transmitted from the negative terminal of the battery through the springs 102 and 100 and through the selectors back to the mid point. The push button K is provided for the purpose of sendin the release impulse over the line, which is required to release the selectors after the called substation has been signaled for a suliicient length of time.

In g- 0 there is shown an arrangement minals of the battery B and the contacts of the relay 107 are reversed, as com ared with the connections to the contacts 0 the relay 106. Thus it will be seen that when the re lay 107 is energized as a result of the engagement of the calling device contact springs 108 and 109, an impulse will be sent through the selectors in one direction, and when the relay 106 is energized as a result of the engagement of the springs 110 and 109, an

impulse will be transmitted over the line in the opposite direction, whereby the same result is accomplished as in Fig. 9. Althou h there are shown two separate batteries I3 and B in Fig. 10, one for controlling the local circuit of the relays and one for operatingthe selector, it will be understood that a single batter might be used. 'It will thus be seen that I ave deviseda simple and efficient station selector and train despatching system and one in which a station may be selected from a large number of stations by the transmission 0 comparatively few impulses, thereby greatly mcreasing the efiiciency of the system.

While I have illustrated my invention in connection with an apparatus in which but three groups of impulses are employed, it will be readily understood that in larger systems additional groups of impulses could be employed, it being merely necessary to add additional arms corresponding to the arms 21 and 22.

It will further be noticed that in the selecting operation the same number of operating impulses are employed to select any station, the selective operation depending merely upon the particular grouping of these impulses. In this manner it requires no longer time to selectively signal the last station on the line than it does the first.

While I have illustrated and described one specific embodiment of my invention, it is to be understood that I do not wish to be limited to the exact construction shown and described.

What I claim as my invention is 1. In a signaling system, a line circuit, a station selector, means responsive to a plurality of impulses transmitted over said line in one direction to operate said selector, and means. responsive to a single reverse current impulse over said line to release said selector when it is in certain positions and responsive only to a plurality of reverse current impulses over said line to release said. selector. when it is in other positions.

2. In a signaling system, a line circuit, a station selector, automatic means responsive to a plurality of impulses transmitted over said line in one direction to operate said selector, automatic means responsive to a single impulse over said line in the reverse direction to release said selector when it is in certain positions, said means responsive only to a plurality of impulses over said line in the reverse direction to release said selector when it is in other positions.

3. In a signaling system, a signaling circuit, means for controlling the same, said means comprising a driving mechanism and a magnet for said mechanism to close the circuit in response to impulses in one direction, and to break the circuit in response to impulses in the reverse direction.

4. In a signaling system, a line circuit, a plurality of switches thereon, each of said switches having electromagnetic means responsive to a group of impulses transmitted over said line circuit in one direction to operate said switches, certain of said switches having devices for preventing their release in response to a reverse impulse, the remainder of said switches having means responsive to said reverse impulse to release them, said electromagnetic means in all of said selectors on said line being then again responsive to impulses over said line circuit in the first direction to operate all of the selectors, the means in said remaining selectors being then responsive to a reverse impulse to release all the said remaining selectors but one, the means in said one being responsive to an additional and consecutive reverse impulse to release said one switch also.

5. In a telephone system, a line circuit, a plurality of station selectors on said line circuit, a signaling circuit for each selector, means for sending impulses of current in one direction or in the reverse direction, progressively movable means in each switch responsive to said impulses whereby a certain definite number of impulses will advance all of the selectors a corresponding number of steps to close all the signaling circuits, and means for releasing said selectors responsive only to two consecutive impulses of the said reverse character.

Signed by me at Chicago, Cook county, Illinois, this 14th day of June, 1912.

JOHN ERIOKSON. 

